The present invention relates to fluid fuel burners and in particular oil burners having atomizing nozzles which are supplied with oil and pressurized air for atomizing the oil. Such burners are typically used in glass melting furnaces and applied vertically downwards through the crown of the furnace ports.
With oil burners of this type, when in normal use, they are fired for a 20-minute period and then shut off for a similar time. During the shut-off period, cooling air is passed through the burner to keep the nozzle cool and clean.
A problem that has developed with this type of burner during the shut-off period, is that when the fuel is shut off, a slight amount of oil remains in the burner and consequently travels to the nozzle. After-burning occurs at the fuel nozzle when the burner is left in the furnace. This after-burning acts to damage the nozzle and shorten its useful life.
In a known prior art device, a burner has an oil shut-off valve which is operated by the oil pressure therein. This burner has the disadvantage that the position of the oil shut-off valve is dependent on the oil pressure and the oil pressure is dependent in turn on the flow to the burner. This means that a highly complex control system is required on each burner to control the oil flow and a reliable shutting off of the oil flow without leaving oil in the nozzle is not obtained.